Sanctum - What is X? Is it the casting cost of the spell returned? it's level? Does the sanctum only reduce your mage's spells cost?
Meditation - 2 attack dice will average a roll of 2. So, you don't gain any mana. Even in the best situation you'd only gain 2 mana. If you want to spend an action to gain mana there is the Meditation Amulet. Also, Meditation should be Mind and not arcane.
Mana Sink - When you say drain, I assume you mean for the target to lose that much mana. I think this one is pretty interesting, but it could also completely lock out several spawnpoints on it's own.
Portal - This is a pretty interesting concept.